Problem 146 - Objective Biology for NEET

Question

Rate of heartbeat is the highest in (a) Whale (b) Elephant (c) Mouse (d) Man

Step-by-Step Solution

Answer

The animal with the highest heartbeat rate is the mouse.

Step 1: Analyze the sizes of the presented animals

Recognize the size differences between the listed animals. Typically, smaller animals have higher heart rates than larger ones. From largest to smallest the order goes: whale, elephant, human, mouse.

Step 2: Identify the Smallest Animal

Based on the size, the smallest animal is the mouse.

Step 3: Conclusion

According to the rule observed in the first step, the smallest animal, which is the mouse, should have the highest heartbeat rate. Therefore, the animal with the highest heartbeat rate among the presented options is the mouse.

Key Concepts

Heart Rate

Heart rate refers to the number of times a heart beats in one minute. It is a vital physiological metric that reflects how an organism's circulatory system is functioning.
Different animals have varying heart rates, with factors such as size, metabolism, and activity level playing crucial roles. In general, smaller animals tend to have faster heart rates. This is due to their higher metabolic rate, which requires rapid circulation of blood to deliver oxygen and nutrients.

For example, a small mouse can have a heart rate exceeding 500 beats per minute, while a whale's heart beats much slower due to its massive size and slower metabolism. Human heart rates fall between these extremes, with a normal range of 60 to 100 beats per minute in resting adults. Understanding heart rates assists in identifying health, assessing fitness levels, and can indicate responses to environmental or physiological stress.

Mammalian Physiology

Mammalian physiology covers a broad spectrum of processes and structures that enable mammals to function and survive. One of its key components is the cardiovascular system, which includes the heart, blood vessels, and blood.
The heart is a crucial organ in mammalian physiology, playing a vital role in sustaining life by pumping blood throughout the body. This organ differs across species in size, efficiency, and rate to meet specific physiological demands.

• In smaller mammals, like the mouse, a faster heart rate is needed to support a high metabolic rate.
• In larger mammals, like the whale, the heart works differently; it operates with fewer beats per minute to manage larger volumes of blood.

Overall, mammalian physiology illustrates adaptation to various environmental niches, showcasing diversity in heart structure and function among different species.

Comparative Anatomy

Comparative anatomy involves studying the structural differences and similarities between different species. This field helps us understand evolutionary adaptations and how organisms have modified their physical features to thrive in vastly different environments.
When looking at heart anatomy across different mammals, we notice direct correlation with both size and metabolic needs. For example:

• Smaller mammals have relatively small hearts that beat quickly to accommodate their rapid metabolisms.
• Larger mammals feature larger hearts with greater stroke volumes, circulating more blood with fewer beats.

The study of anatomical differences provides insights into the physiological strategies employed by different species to manage energy and survive. Understanding these differences also sheds light on the evolutionary pressures that have shaped the diverse life forms we see today.